Is my platy ok?

[Vlowman]

I'd be grateful for your thoughts.

I'm pretty sure my water is fine (I test and water change regularly) but this one platy is concerning me. In some lights he looks fine, like this:

But when the light catches him in a certain way it looks like he's losing scales, like this:

And while he generally goes about his business looking ok, he sometimes follows another, smaller male around (it's an all male tank) and gentle rubs up against him. I haven't seen him rub against any rocks or anything else.

All advise or thoughts most appreciated.

 

[emeraldking]

There's nothing wrong with him. He's got some mirror scales. It means that a number of scales have got iridophores (iridescent color cells) besides the xanthophores (yellow color cells) and erythrophores (red color cells). Which means that the light will be reflected once the light hits those scales.
The chasing towards the other male, has got to do with dominance. So, not aggression of any kind. If you've got a one gender tank ( just males or just females), you'll see that a pecking order will be at hand at some point. Dominant and submissive specimens will be shown. The more dominant specimens will behave like a male and a submissive specimen takes the female role. Quite normal. In general, nothing to be worried about. The behavior will pass most of the time, once every fish knows his/her place.

 

[Vlowman]

There's nothing wrong with him. He's got some mirror scales. It means that a number of scales have got iridophores (iridescent color cells) besides the xanthophores (yellow color cells) and erythrophores (red color cells). Which means that the light will be reflected once the light hits those scales.

Thanks very much indeed. Glad I don't have some sort of illness in the tank!